In Bird Friendly Cities, key threats to birds are effectively mitigated, and nature is restored so native bird populations can thrive.

Helpful Resources

  • Thom Luloff

Pesticides and Herbicides

Every tool has a purpose and an appropriate scope for usage. We need to choose the tool that does the most effective job, with the least amount of collateral effect.


Pesticides and herbicides are products with chemical compounds that work by targeting living cells to kill, deactivate, or deter unwanted pests or plants. There are suitable and targeted applications for these compounds which may be necessary, such some invasive species removal programs, but these compounds do come with an environmental cost and shouldn’t be our first and only solution to deal with pests or weeds.


Indiscriminate usage of pesticides and herbicides products has had profound consequences on our ecosystems; the most telling was the widespread application of DDT in the years following World War II. DDT (dichloro-diphenyl-trichloroethane) belongs to a class of pesticides known as organochlorides and is an exceptionally potent insecticide; increasing some crop yields by 20% by removing pest damage. Despite making economic sense, the issue with DDT is that it persists for 10-15 years in the environment following application and is also fat soluble (meaning it builds up in fatty tissues) leading to food chain bioaccumulation. Small doses of DDT consumed by crayfish, frogs, and fish bioaccumulate into larger doses in predators near the top of the food chain such as eagles, hawks, pelicans, condors, and humans. After decades of bioaccumulation, birds with high levels of DDT in their bodies were laying eggs that had shells so thin they broke before hatching, causing bird populations to plunge. By 1963, only 417 nesting pairs of Bald Eagles were found in the lower 48 United States!


Though continued usage of DDT does persist, in 2004, the treaty known as the Stockholm Convention on Persistent Organic Pollutants (POPs), which was signed by 170 countries restricting the use of DDT to emergency insect control.


So where does this leave us? Are herbicides and pesticides bad?

Well they certainly can be if used inappropriately, but like everything else, these compounds are tools that need to be used sparingly and with respect for environmental consequences - and not as the first response.


For pests: Integrated Pest Management (IPM) is a process that uses all necessary techniques to suppress pests effectively, economically, and in an environmentally sound manner. Fortunately for us, birds are one of the BEST (and free!) pest managers around - biting insects, garden pests, rodents - there is a bird for that!


For unwanted weeds, and invasive species: we do need to think creatively about solutions before resorting to chemical applications and there are some great suggestions:

  1. Mulching. Nature leaves us dead leaves and detritus each year that not only blocks out light for weed seeds to germinate but also enriches the soil AND provides shelter and refuge for overwintering amphibians, insects, and small mammals

  2. Solarizing your soil involves covering an area of weedy ground with a clear, heavy plastic sheet. Leave the sheet in place for 4 to 6 weeks, and remove only once all the weeds are brown and dry.

  3. Boiling Water. Boil a kettle of water and pour it over any weeds to burn them. This technique is great for weeds growing in the cracks of pavement and coming up in your garden paths.

  4. Vinegar Sprays. Vinegar as a weak acid will dry and stress weed plants if sprayed directly on the leaves. You may have to apply it multiple times. Mix the following into a spray bottle and spray directly onto your weeds in full sun:

  • 1 litre 5% white household vinegar

  • 1 cup table salt

  • 1 Tbsp. dish soap